1. Field of the Invention
The present invention relates to a thermal development method and apparatus for generating an image from a latent image recorded on an image formation layer of a photosensitive photothermographic recording material, by means of heating the photosensitive photothermographic recording material.
2. Description of the Related Art
An image forming apparatus called, e.g., a medical imager, produces a print with a visible image from an image captured by a medical measuring machine, such as a CT or MRI device. The image forming apparatus employs a photosensitive photothermographic recording material (also called a “recording material”) produced by forming a photothermographic image formation layer on a support such as a PET film or the like. This photosensitive photothermographic recording material is exposed to a light beam which has been modulated in accordance with image data supplied from an image data supply source, such as an MRI device, to thus record the latent image. Subsequently, the exposed photosensitive photothermographic recording material is subjected to heating development performed by a built-in thermal development section, to thus generate colors and output a hard copy.
FIG. 8 shows an imaging forming apparatus equipped with a related-art thermal development apparatus (See JP-A-11-218894 (FIG. 1)).
An image-forming apparatus 1 basically comprises, in sequence in a direction in which a recording material A is conveyed (hereinafter called a “conveyance direction of a recording material A”), a recording material feed section 3, an image exposure section 5, and a thermal development section 7. The recording material feed section 3 takes a sheet of recording material A from a magazine 9 and supplies the recording material A downstream in the conveyance direction. The image exposure section 5 is a section which exposes the recording material A to a light beam scan to record an image, and comprises an exposure unit 11 and sub-scan conveyance means 13.
The recording material A on which the latent image is recorded by the image exposure section 5 is conveyed upward to the thermal development section 7 by a pair of conveyance rollers 15 and 17. The thermal development section 7 is a section which heats the recording material A through use of a heating drum 19 serving as heating means, to thereby render the latent image visible through thermal development, and comprises an endless belt 21, a separation claw 23, and support rollers 25a to 25d for supporting the endless belt 21.
The recording material A transported to the thermal development section 7 is conveyed between the heating drum 19 and the endless belt 21 and sandwiched between the heating drum 19 and the endless belt 21 by means of rotation of the heating drum 19. The recording material A is transported while remaining in intimate contact with the heating drum 19 and is subjected to thermal development effected by the heat of the heating drum 19, whereby the latent image recorded by means of exposure becomes visible. In this case, only one side of the recording material A is heated by the heating drum 19. When the extremity of the thus-thermally-developed recording material A has reached the neighborhood of the separation claw 23, the separation claw 23 comes into contact with the heating drum 19 and intrudes between the heating drum 19 and the recording material A, whereupon the recording material A is exfoliated from the heating drum 19 and output to a discharge tray 27.
Specifically, the recording material loaded into the thermal development section is conveyed while being nipped between a heating drum and an endless belt and thermally developed by the heat of the heating drum, whereby the recorded latent image becomes visible through exposure. Namely, the recording material is heated from only one side by the heating drum.